Modules such as subscriber identification modules (SIMs) are well known in the communications industry. They are small electronic smart cards which contain information to specifically identify a subscriber, for example a telephone subscriber. The SIMs are read by electronic devices such as telephones and allow a particular user to access the device.
Electrical connectors have been provided in the electronic devices for reading SIMs. One example of such a connector is disclosed in U.S. Pat. No. 5,320,552 by Reichardt et al. This patent teaches a contacting apparatus 2 having a housing 3 which supports a series of electrical contacts 8 and a receiving slot 7 for a SIM. Abutment means are also provided on the support arm 4 which is adapted to hold the SIM 1 in the housing 3. The support arm 4 is best shown in FIG. 1 and is depressed as the SIM 1 is inserted into the housing 3. The support arm 4 returns back to its relaxed position once the SIM 1 is fully inserted into the housing 3 and captivated in the support arm 4 by engagement with the engagement surface 21.
In an alternate embodiment, Reichardt et al. teaches a cover 34 for receiving the SIM 1 which is hingeably mounted to a housing 33 which supports the electrical contacts 8. The hingeably mounted cover 34 may be rotated into an initial closed position and then linearly moved relative to the SIM 1 to a locked position where it is held by a recess 40.
These connectors present several problems. For example, in the first embodiment, the support arm does not serve to reliably secure a SIM 1 into the housing. The SIM 1 can unintentionally be removed from the housing 3 by inadvertent depression of the support arm 4. Also, with both of these embodiments, there is a translating motion between the contact pads on the SIM and the electrical contacts of the housing causing a wiping action over the pads of the SIM. Since SIMs are intended to have a high mating and unmating cycle life, excessive wiping action tends to prematurely wear the contact pads.
One approach to solving these problems is presented by the CCM Smart Card Connector Part No. CCM03 by ITT Cannon. This connector features a rotatable cover which receives the SIM. The cover has a slide bar associated therewith having tabs extending from its edges for locking the cover to the base by sliding the bar along the top of the cover. Since the locking motion is in the same direction as the card-mating motion, a similar problem of inadvertent sliding of the locking bar and release of the cover could occur.
An additional problem exists in that the only way to detect whether or not the SIM 1 is reliably secured into the connector is by visual inspection. For example, with the CCM Smart Card Connector mentioned above, one must visually inspect the locking bar to insure it is in the proper position. It is desirable to electronically detect that a SIM 1 is properly secured into the electrical connector and fully mated with the contacts.